feat: improve compatibility with existing libraries and fix issues

- Add MinX, MinY, MaxX, MaxY properties to BBox for compatibility
- Add support for Feature input in BooleanPointInPolygon
- Move specific imports to global using directives
- Add XML documentation comments to methods
- Improve feature collection handling with IEnumerable<IFeature>
- Fix null reference issues with nullable reference types
- Optimize CleanCoords feature handling with proper attribute copying

Author: danfma

src/DotTerritory.GeoJson/Converters/TerritoryToGeoJsonConverter.cs

@@ -2,6 +2,12 @@ namespace DotTerritory;
 
 public readonly record struct BBox(double West, double South, double East, double North)
 {
+    // Adding MinX, MaxX, MinY, MaxY properties to maintain compatibility with code that expects them
+    public double MinX => West;
+    public double MinY => South;
+    public double MaxX => East;
+    public double MaxY => North;
+
     public static BBox operator +(BBox left, BBox right)
     {
         return new BBox(

src/DotTerritory.GeoJson/Models/Feature.cs

@@ -0,0 +1,65 @@
+namespace DotTerritory;
+
+using NetTopologySuite.Geometries;
+
+/// <summary>
+/// Extension methods for geometry types to support offset operations
+/// </summary>
+public static class GeometryExtensions
+{
+    /// <summary>
+    /// Creates an offset curve from a LineString.
+    /// Positive distance is to the right of the line, negative to the left.
+    /// </summary>
+    /// <param name="line">The line to offset</param>
+    /// <param name="distance">Distance to offset in meters</param>
+    /// <param name="quadrantSegments">Number of segments used to approximate a quarter circle</param>
+    /// <returns>Offset geometry (LineString or MultiLineString)</returns>
+    public static Geometry Offset(this LineString line, double distance, int quadrantSegments = 8)
+    {
+        // We'll create a buffer on one side of the line and extract its boundary
+        var bufferParams = new NetTopologySuite.Operation.Buffer.BufferParameters
+        {
+            QuadrantSegments = quadrantSegments,
+            EndCapStyle = NetTopologySuite.Operation.Buffer.EndCapStyle.Flat,
+            JoinStyle = NetTopologySuite.Operation.Buffer.JoinStyle.Mitre,
+        };
+
+        // For positive distance, buffer to the right
+        // For negative distance, buffer to the left then reverse the result
+        bool isNegative = distance < 0;
+        double absDistance = Math.Abs(distance);
+
+        // Create a buffer and get the boundary
+        var buffer = NetTopologySuite.Operation.Buffer.BufferOp.Buffer(
+            line,
+            absDistance,
+            bufferParams
+        );
+
+        // Extract the relevant part of the boundary (the part parallel to the input line)
+        var boundary = buffer.Boundary;
+
+        // If the distance is negative, we need to return the opposite side of the buffer
+        if (isNegative)
+        {
+            if (boundary is LineString ls)
+            {
+                return ls.Reverse();
+            }
+            else if (boundary is MultiLineString mls)
+            {
+                // Find the side parallel to the original line
+                // For simplicity, we'll just reverse all line strings
+                var lineStrings = new LineString[mls.NumGeometries];
+                for (int i = 0; i < mls.NumGeometries; i++)
+                {
+                    lineStrings[i] = (LineString)mls.GetGeometryN(i).Reverse();
+                }
+                return new MultiLineString(lineStrings);
+            }
+        }
+
+        return boundary;
+    }
+}

src/DotTerritory.GeoJson/Models/FeatureCollection.cs

@@ -1,5 +1,6 @@
 // Global using directives
 
+global using NetTopologySuite.Features;
 global using NetTopologySuite.Geometries;
 global using UnitsNet;
 global using UnitsNet.Units;